Method and system for regional data network configuration in wireless communication network

ABSTRACT

Disclosed is a 5G or pre-5G communication system for supporting a data transmission rate higher than that of a 4G communication system such as LTE. According to an embodiment of the present invention, a method of a terminal in a wireless mobile communication system comprises the steps of: receiving data network information including data network access permission region information and data network identification information; checking whether the terminal enters a data network access permission region, on the basis of the data network information; and performing a data network access procedure on the basis of the checking result.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.16/827,377, filed Mar. 23, 2020, which is a continuation of U.S.application Ser. No. 16/327,743, filed Feb. 22, 2019, now U.S. Pat. No.10,602,472, which is a 371 National Stage of International ApplicationNo. PCT/KR2017/009103, filed Aug. 21, 2017, and which claims the benefitof U.S. Provisional Application No. 62/377,888, filed Aug. 22, 2016 andclaims priority to Korean Patent Application No. 10-2016-0130903, filedOct. 10, 2016, Korean Patent Application No. 10-2017-0032029, filed Mar.14, 2017 and Korean Patent Application No. 10-2017-0051738, filed Apr.21, 2017, the disclosures of which are herein incorporated by referencein their entireties.

BACKGROUND 1. Field

The present disclosure relates to a method and a device for selecting acell in a mobile communication system, and more particularly, to amethod and a device for selecting a cell, which enable a base station totransmit data not only in a licensed frequency band but also in anunlicensed frequency band.

2. Description of Related Art

To meet the demand for wireless data traffic having increased sincedeployment of 4G communication systems, efforts have been made todevelop an improved 5G or pre-5G communication system. Therefore, the 5Gor pre-5G communication system is also called a ‘beyond 4G network’ or a‘post LTE system’.

The 5G communication system is considered to be implemented in higherfrequency (mmWave) bands, e.g., 60 GHz bands, so as to accomplish higherdata rates. To decrease propagation loss of the radio waves and increasethe transmission distance, beamforming, massive multiple-inputmultiple-output (MIMO), full dimensional MIMO (FD-MIMO), array antenna,analog beamforming, and large scale antenna techniques are discussed in5G communication systems.

In addition, in 5G communication systems, development for system networkimprovement is under way based on advanced small cells, cloud radioaccess networks (RANs), ultra-dense networks, device-to-device (D2D)communication, wireless backhaul, moving network, cooperativecommunication, coordinated multi-points (CoMP), reception-endinterference cancellation and the like.

In the 5G system, hybrid FSK and QAM modulation (FQAM) and slidingwindow superposition coding (SWSC) as an advanced coding modulation(ACM), and filter bank multi carrier (FBMC), non-orthogonal multipleaccess (NOMA), and sparse code multiple access (SCMA) as an advancedaccess technology have been developed.

On the other hand, in the 3GPP that is in charge of cellular mobilecommunication standards, a new core network structure is called a 5Gcore (5GC), and the standardization thereof is in progress to achieveevolution from the existing 4G LTE system into a 5G system.

In comparison to an evolved packet core (EPC) that is a network core forthe existing 4G, the 5GC supports the following discriminatoryfunctions.

First, in the 5GC, a network slice function is introduced. In accordancewith the 5G requirements, the 5GC should support various terminal typesand services. For example, services provided in the 5G may includeenhanced mobile broadband (eMBB), ultra-reliable low-latencycommunications (URLLC), and massive machine type communications (mMTC)services. Such terminals and services have different requirements withrespect to the core network.

For example, the eMBB service may require a high data rate, whereas theURLLC service may require a high stability and low latency.

Technology proposed to satisfy such various service requirements is anetwork slice scheme. The network slice is a method for making severallogical networks through virtualization of one physical network, andrespective network slice instances (NSIs) may have differentcharacteristics since they may have network functions (NFs) to matchtheir characteristics. Accordingly, the 5G network can efficientlysupport several 5G services through assignment of the NSIs matching thecharacteristics of the required services to respective terminals.

Second, the 5GC can easily support network virtualization paradigmsthrough separation of a mobility management function and a sessionmanagement function from each other. In the existing 4G LTE, allterminals can be provided with services in the network through signalingexchanges with single core equipment called a mobility management entity(MME) that is in charge of registration, authentication, mobilitymanagement, and session management functions. However, in the 5G, thenumber of terminals is explosively increased, and the mobility andtraffic/session characteristics that should be supported in accordancewith the terminal types are sub-divided. In this case, if the singleequipment, such as the MME, supports all the functions, scalability toadd entities for necessary functions cannot help being deteriorated.Accordingly, in view of the function/implementation complexity of thecore equipment that is in charge of a control plane and signaling load,various functions for scalability improvements have been developed basedon a structure for separating the mobility management function and thesession management function from each other.

In the LTE system, all IP traffics from terminals are anchored at aPDN-GW. Further, for latency improvement in a backhaul network, local IPaccess (LIPA) and selected IP traffic offloading (SIPTO) have beenproposed to locate an IP anchor close to the terminal. In such astructure, a PDN connection of the terminal is established, but there isno way to automatically establish or disconnect the PDN connection inaccordance with the location of the terminal.

The present disclosure proposes a method for discovering a local areadata network available in a place where a terminal is located, andestablishing, disconnecting, or disabling a PDU session for connectingthe data network of the terminal in accordance with the location of theterminal.

SUMMARY

In the 3GPP evolved packet core network that is the existing 4G mobilecommunication network, there is no way to provide information on a datanetwork available to a terminal in accordance with the location of theterminal, to establish a session connection for transmission/receptionof a packet data unit with the terminal, and to enable/disable theestablished session in accordance with the location of the terminal. Thepacket data unit that is transmitted or received with respect to theterminal may be an IP datagram, Ethernet frame, or unstructured packet.

In other words, there exists no method for providing a data networkconnection through which packet transmission/reception is possible onlyin a specific location. Accordingly, it is not possible for a networkoperator to provide a local area data network service that makes itpossible to use a data network only in a specific area.

The present disclosure proposes a method for providing, to a terminal,data network information available in an area where the terminal iscurrently located, establishing a data network session usable in thecorresponding area using the available data network information providedto the terminal, and disconnecting or temporarily interrupting (ordisabling) the established session if the terminal gets out of an areawhere the terminal is allowed to transmit or receive the data session.

Further, the present disclosure proposes a method for reactivating orresuming the temporarily interrupted (or activated) session when theterminal moves again to the area where the terminal is allowed totransmit or receive the session in a state where the session of theterminal is established.

In one aspect of the present disclosure, a method of a terminal includesreceiving data network information including data network access allowedarea information and data network identification information;identifying whether to enter a data network access allowed area based onthe data network information; and performing a data network accessprocedure based on the result of the identification.

In another aspect of the present disclosure, a method of a networkentity includes transmitting, to a terminal, data network informationincluding data network access allowed area information and data networkidentification information; receiving a service request from theterminal; identifying whether it is possible to provide a service to theterminal based on a location of the terminal and the data networkinformation; and providing the service to the terminal based on theresult of the identification.

In still another aspect of the present disclosure, a terminal includes atransceiver configured to transmit and receive signals; and a controllerconfigured to receive data network information including data networkaccess allowed area information and data network identificationinformation, identify whether to enter a data network access allowedarea based on the data network information, and perform a data networkaccess procedure based on the result of the identification.

In yet still another aspect of the present disclosure, a network entityincludes a transceiver configured to transmit and receive signals; and acontroller configured to transmit, to a terminal, data networkinformation including data network access allowed area information anddata network identification information, receive a service request fromthe terminal, identify whether it is possible to provide a service tothe terminal based on a location of the terminal and the data networkinformation, and provide the service to the terminal based on the resultof the identification.

In an embodiment of the present disclosure, a session access allowedarea (data network (DN) service area) may be defined using a trackingarea list or a cell list.

In an embodiment of the present disclosure, the terminal may detectentry into or exit from the DN service area through identification ofthe defined DN service area.

In an embodiment of the present disclosure, in order to notify a networkwhether an established session is activated or deactivated when theterminal detects the entry into or the exit from the DN service area,the terminal may perform a tracking area update procedure, or a 5Gsystem may perform a registration update procedure. Further, as anothermethod, in an embodiment of the present disclosure, when the terminaldetects the entry into or the exit from the DN service area, theterminal may perform the registration update procedure in order todisable or disconnect a session in a 5G core network.

In an embodiment of the present disclosure, when the terminal secedesfrom the DN service area, the network may disable the session of theterminal without disconnecting the session of the terminal. In a statewhere the session of the terminal is deactivated, the terminal and thenetwork may discard transmitted or received packets.

In an embodiment of the present disclosure, if the terminal returns tothe DN service area, the session of the terminal may be resumed orreactivated. The terminal may perform a registration update procedure toenable the network to update the session state of the terminal.

In an embodiment of the present disclosure, if the terminal gets out ofthe DN service area, the terminal may perform a tracking area updateprocedure, that is, a registration update procedure, to notify an accessand mobility management function (AMF) managing mobility of the terminalin the network that the session state of the terminal has been changed.

The AMF may notify a session management function (SMF) that the sessionstate has been changed. Accordingly, the SMF may change the sessionstate to a deactivated state since the terminal is not located in the DNservice area. In the network, a user plane function that is in charge oftransmission/reception of user traffic of the session under the controlof the SMF may discard downlink traffic.

In an embodiment of the present disclosure, in a network where a localarea data network (LADN) is supported, session establishment may not beallowed in a place that is not a session establishment allowed area ofthe terminal. When the terminal sends a session establishment requestfor connection to the LADN, the AMF determines whether the LADNconnection is possible in an area where the terminal is currentlylocated. The AMF may transfer an indicator indicating whether the LADNconnection is possible to the SMF.

According to an embodiment of the present disclosure, it is possible toprovide a session connection method if a terminal is located in aspecific area.

According to an embodiment of the present disclosure, it is possible toprovide a method for providing, to a terminal, data network informationavailable in the corresponding area when the terminal performs aninitial registration procedure in a network or a registration updateprocedure.

According to an embodiment of the present disclosure, a terminal canconnect to a data network in an area where data network access ispossible. Further, if the terminal gets out of an access allowed areaafter successfully connecting to the data network through a data networkconnection procedure, the session of the terminal may be deactivated.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating an example of configuration of a datanetwork access allowed area;

FIG. 2 is a diagram illustrating the concept of a local area datanetwork and the contents of a data network access allowed area;

FIG. 3 is a diagram illustrating information flows among a terminal(UE), AMF, and SMF;

FIG. 4 is a diagram illustrating a network structure including a PCF;

FIG. 5 is a diagram illustrating activated and deactivated states of asession for local area data network support;

FIG. 6 is a diagram illustrating a data network service areaconfiguration method according to an embodiment of the presentdisclosure;

FIGS. 7A and 7B are diagrams illustrating an example of a data networkservice area configuration method according to an embodiment of thepresent disclosure;

FIGS. 8A and 8B are diagrams illustrating a procedure in which aterminal receives local area data network information;

FIGS. 9A and 9B are diagrams illustrating a local area data networksession establishment procedure;

FIG. 10 is a diagram explaining a local area data network sessionservice request procedure;

FIG. 11 is a diagram illustrating the structure of a terminal accordingto an embodiment of the present disclosure;

FIG. 12 is a diagram illustrating the structure of an AMF according toan embodiment of the present disclosure; and

FIG. 13 is a diagram illustrating the structure of an SMF according toan embodiment of the present disclosure.

DETAILED DESCRIPTION

Hereinafter, embodiments of the present disclosure will be described indetail with reference to the accompanying drawings. In the accompanyingdrawings, it is to be noted that the same drawing reference numerals areused for the same elements if possible. Further, detailed explanation ofknown functions and configurations that may obscure the subject matterof the present disclosure will be omitted.

In describing the embodiments of the present disclosure, explanation ofthe technical contents that are well known in the art to which thepresent disclosure pertains and are not directly related to the presentdisclosure will be omitted to avoid obscuring the subject matter of thepresent disclosure and to transfer the same more accurately.

For the same reason, in the accompanying drawings, some constituentelements are exaggerated, omitted, or roughly illustrated. Further,sizes of some constituent elements may not completely reflect the actualsizes thereof. In the drawings, the same drawing reference numerals areused for the same elements across various figures.

The aspects and features of the present disclosure and methods forachieving the aspects and features will be apparent by referring to theembodiments to be described in detail with reference to the accompanyingdrawings. However, the present disclosure is not limited to theembodiments disclosed hereinafter, but can be implemented in diverseforms. The matters defined in the description, such as the detailedconstruction and elements, are nothing but specific details provided toassist those of ordinary skill in the art in a comprehensiveunderstanding of the disclosure, and the present disclosure is onlydefined within the scope of the appended claims. In the entiredescription of the present disclosure, the same drawing referencenumerals are used for the same elements across various figures.

First, in an embodiment of the present disclosure, the concept of alocal area data network, a network structure, and a method forimplementing the same will be described.

A local area data network means a data network which a terminal (UE) canconnect to through a session only in case where the terminal is locatedin a specific area. The area where the terminal is allowed to connectthe local area data network may be called a local area data networkzone, which can be identified by a list of tracking areas. The detailedcontents will be described later.

In the present disclosure, the local area data network zone may bemixedly used with a data network allowed area, a data network accessallowed area, a data network service area, and a data networkserviceable area.

Accordingly, in a 5G system, the terminal can connect to the local areadata network in the local area data network zone. The local area datanetwork can be used for supporting an enterprise network (internalnetwork), stadium, special event, concert, and IoT service.

Configuration information of the local area data network (it may also becalled an available data network) may be configured initially in anetwork (e.g., AMF), and may be known to the terminal in a process inwhich the terminal performs an initial registration or registrationupdate procedure. Accordingly, using the information known to theterminal, the terminal may determine that it is located in the localarea data network zone (it may also be called a data network accessallowed area), and may start a session establishment procedure if anexecution of an application program is requested. Further, the terminalmay be located in the data network access allowed area, and if theexecution of the application program is requested, it may start thesession establishment procedure in accordance with a terminal routingselection policy. Further, if the terminal enters the data networkaccess allowed area in case of requesting the execution of theapplication program, the terminal may start the session establishmentprocedure.

As described above, the local area data network can be used forsupporting the enterprise network, stadium, special event, concert, andIoT service.

First, the present disclosure proposes a method for defining the localarea data network.

As the method for defining the local area data network zone (datanetwork access allowed area), four methods as in Table 1 below may beconsidered.

TABLE 1 Unit of local area data network zone Merits Demerits Trackingarea Existing tracking Dependency exists in area is reused. trackingarea. Newly defined Optimum area Change of RAN area configurationstandards is possible. is necessary. Mobile The smallest unit Lowflexibility communication network cell RAN paging area Suited to aOperable only in an narrow area active state from a viewpoint ofterminal core network

As described above, the unit of the local area data network zone may bedefined by various methods. In an embodiment of the present disclosure,it is proposed to reuse the tracking area in the minimum unit of thelocal area data network zone.

Accordingly, in an embodiment of the present disclosure, the local areadata network zone is configured in the unit of a tracking area, and thelocal area data network zone in the unit of a tracking area can beconfigured independently of a registration area in the 5G system thatthe terminal receives in a registration or registration update procedureor a tracking area index list in the 4G system.

Through an initial registration procedure or registration updateprocedure of the terminal, the network notifies the terminal of theregistration area (in the 4G system, corresponding to TAI list) and alist of data network access allowed areas available in the registrationarea.

FIG. 1 is a diagram illustrating an example of configuration of a datanetwork access allowed area.

As described above, the present disclosure proposes a method fordefining a data network access allowed area with a list of trackingareas with respect to one terminal session. Such an area is configuredin accordance with an operator's policy.

Referring to FIG. 1 , local area data network (LADN) zone 1 (120) wherethe terminal is allowed to connect to a local area data network 110 maybe composed tracking areas 1 to 4 (TA1 to TA4 (121 to 124)).

Accordingly, the terminal can detect entry into or exit from the datanetwork access allowed area through identification of the tracking area.When the terminal detects the entry into or the exit from the datanetwork access allowed area, it can perform a registration updateprocedure to notify the network whether or not a terminal session is ina usable state.

In the same manner, FIG. 2 is a diagram illustrating the concept of alocal area data network and the contents of a data network accessallowed area.

Referring to FIG. 2 , local area data network (LADN) zone 1 (215) wherethe terminal is allowed to connect to a local area data network 1 (210)may be composed TA1 to TA4 (211 to 214).

Further, a registration area 205 where the terminal is allowed toconnect to data network 0 (200) may include LADN zones 1 to 3, and theterminal can receive information on the registration area and the LADNzone through the registration update procedure.

Second, the present disclosure proposes a method for determining whethera network triggers a PDU session establishment when a terminal enters adata network access allowed area.

It is not always necessary for the network to trigger the sessionestablishment. When the terminal enters a specific area, an applicationprogram of the terminal that requests a notification service mayestablish the session by requesting the session establishment just afterbeing notified of entry into the corresponding area. Accordingly,instead of the session establishment through triggering by the network,it is proposed to add an indicator indicating immediate sessionestablishment when the terminal enters the data network access allowedarea.

Accordingly, it is proposed to add information on a session type that isnecessary for the immediate session establishment when the terminalenters the data network access allowed area.

The terminal receives information on a session in which the terminalaccess is allowed and an area where the session is allowed in aregistration area (TAI list) received while the terminal performs aninitial registration procedure or a registration update procedure in thenetwork. Such information may include an immediate setup indicator whenthe terminal enters the data network access allowed area.

If the immediate setup indicator is not included in the information, theterminal may start a session establishment procedure at a necessary timein the data network access allowed area.

Third, the present disclosure proposes a method in which a networkprovides information on an available local area data network to aterminal.

In an embodiment of the present disclosure, three methods as in Table 2below may be considered.

TABLE 2 Accessible data network information transfer method MeritsDemerits Broadcast Pre-configuration Overhead of a broadcasting ornotification message for information transfer for each terminalDifferent configurations for is unnecessary. terminals are impossible.Change of RAN is necessary. Provisioning in Configurations If a terminalis far apart from the terminal for terminals are corresponding area,unnecessary possible. information is configured. Information isConfigurations notified for for terminals are each terminal. possible.

Among the above-described methods, in an embodiment of the presentdisclosure, a method for notifying the information for each terminal isproposed. However, the embodiment of the present disclosure is notlimited thereto.

According to the method for notifying the information for each terminal,the network notifies the terminal of the information on the data networkaccess allowed area through an initial registration or registrationupdate procedure of the terminal or a separate procedure for notifyingthe data network access allowed area.

Fourth, the present disclosure proposes a method for disconnecting asession if a terminal leaves from a data access allowed area.

In accordance with the terminal movement, it is not preferable toimmediately disconnect the session when the terminal gets out of thedata access allowed area. This is because the terminal may immediatelyreturn to the data access allowed area. In this case, if the session isdisconnected and then is reestablished again, the network is required toperform a procedure for allocating an IP address of the terminal and aprocedure for generating a tunnel (N3 tunnel) between a base station anda core network, and thus complexity is increased.

According to an embodiment of the present disclosure, if the terminalgets out of the data access allowed area, the session may be deactivatedinstead of session disconnection. If the session is deactivated, theterminal and the network may discard the traffic for the correspondingsession. Further, the terminal may notify the network that the terminalhas left from the data network access allowed area.

Further, when the terminal returns to the data network access allowedarea, the session may be activated. The terminal performs a registrationupdate procedure for updating the location of the terminal so that thenetwork can update the session state.

Accordingly, session deactivated and activated states as in Table 3below are proposed.

TABLE 3 Session states in accordance with terminal locations In a dataaccess Outside a data access allowed area allowed area PDU sessionEnabled Disabled established (activated) state (deactivated) state PDUsession non- Unavailable state Available state established

Fifth, the present disclosure proposes a method for minimizing signaltransfer if a terminal repeats entry into and exit from a data networkaccess allowed area.

In order to match the session state between the terminal and the networkin a scenario that the terminal repeats the entry into and exit from thedata network access allowed area, it is required to send and receive alarge amount of signal processing messages between the terminal and thenetwork.

If the tracking area is changed in an active state of the terminal, ahandover procedure is accompanied, and the amount of signal processingmessage is further increased.

In an idle state of the terminal, an overhead of the signal processingmessages becomes severer. This is because, in the idle state of theterminal, a procedure for transitioning the state of the terminal isperformed, and thus it is required to transmit or receive a largeramount of signal processing messages. In particular, if there is no datato be transmitted or received through the terminal and the network,great resources may be wasted.

In order to solve such a problem, the present disclosure proposes a lazyupdate method with respect to a terminal in an idle state. This isbecause the terminal is not required to update the state of the networkin case where the terminal does not transmit or receive data.

Accordingly, in an embodiment of the present disclosure, a lazy statusupdate in a session deactivated state is proposed.

According to the present disclosure, the terminal does not perform aregistration update procedure when it enters into or leaves from thedata network access allowed area in an idle state. Accordingly, in casewhere the terminal is located in the data network access allowed areaand there is data to be transmitted in the session deactivated state,the terminal may perform the registration update procedure to change thesession state.

Further, if downlink data that is directed from the network to theterminal arrives at a user plane function (UPF) while the terminal islocated outside the data network access allowed area, the network sendsa paging message to the terminal, and the terminal perform a servicerequest procedure to respond to the paging.

When such a procedure is performed, the network identifies whether theterminal can use the session in the area where the terminal is currentlylocated. If it is identified that the area where the terminal iscurrently located is the area where the terminal is unable to use thesession, the network may reject a service request of the terminal. Insuch a procedure, the session state is changed to a deactivated state.

Hereinafter, the network structure and procedure for providing a localarea data network according to an embodiment of the present disclosurewill be described. The procedure described hereinafter includestransferring information on a data network allowable area to a terminal,establishing and maintaining a session, and enabling/disabling thesession.

As described above, the local area data network is a data network whichthe terminal can connect and access only in a specific preconfiguredarea, that is, in a data network access allowed area (i.e., LADN zone orDN allowed area). The data network access allowed area is a logical areain which the location of the terminal can be tracked in the 5G system.One data network access allowed area may be implemented by a set oftracking areas or cells.

Referring to FIG. 1 as described above, local area data network 1 (110)can be connected only in an area where the terminal is located in thedata network access allowed area 1 (LADN zone 1 (120)) consisting of TA1(121), TA2 (121), TA3 (123), and TA4 (124).

That is, one 5G base station (in the drawing, NextGen Node-B (NG-NB)which may include an eLTE base station and a new radio base station) mayprovide a plurality of LADN zones. In the drawing, NG-NB1 130 canprovide a service with respect to parts of LADN zone 1 (120) composed ofTA1, TA2, TA3, and TA4, and LADN zone 2 (140) including TA5 (141) andTA6 (142).

With the network structure, an embodiment of the present disclosure hasthe following characteristics.

1) The data network access allowed area is an area where the terminal isallowed to connect the data network through the session, and can bedefined by a set of tracking areas or a set of cells.

2) The data network access allowed area can be configured for eachsession of the terminal. The data network access allowed area can beconfigured statically or dynamically in accordance with terminalsubscription information and operator's policy.

3) The data network access allowed area for the session can bepreconfigured by an AMF that manages mobility of the terminal in thenetwork.

4) When the terminal performs an initial registration procedure or aregistration update procedure, the AMF can notify the terminal ofavailable local area network information.

5) While the terminal is located in the data network allowable area, itcan establish the session in accordance with the operator's policy. Thepolicy information for the terminal may include information on a policythat prescribes the operation of the terminal when the terminal entersinto or exits from the data network allowed area. For example, the LADNentry policy may instruct the terminal to perform the sessionestablishment procedure when the terminal enters the data networkallowed area, or may instruct the terminal to notify the network of thecurrent location of the terminal through the registration updateprocedure.

6) While the terminal is located outside the data network allowablearea, the session is deactivated. In another method, if the terminalgets out of the data network access allowed area, the terminal maynotify of the current location of the terminal so that the core networkdisconnects the session. For example, the terminal transfers aregistration request message to the AMF. The AMF may instruct the SMF todisconnect the session after identifying the location of the terminal.

The LADN exit policy can instruct the terminal to operate when theterminal monitors the exit from the data network access allowed area.For example, the LADN exit policy can instruct the terminal to perform asession disconnect procedure for the local data network, or to performthe registration update procedure for notifying the network of thecurrent location of the terminal so that the network disconnects ordisables the session.

7) The data network access allowed area information may be transferredto the terminal during the session establishment procedure.

8) If the terminal detects entry into or exit from the data networkaccess allowed area by identifying the tracking area, it may perform theregistration update procedure to manage the state of the terminal. Ifthe terminal detects the entry into the data network access allowed areaby identifying the tracking area and the current cell information, itperforms the registration update procedure to notify the core network ofthe current location of the terminal in accordance with the LADN policyinformation of the terminal.

The LADN policy information means information received through a policycontrol function (PCF) of the core network. FIG. 3 illustratesinformation flows among an AMF, SMF, and terminal (UE).

FIG. 3 is a diagram illustrating information flows among a terminal(UE), AMF, and SMF.

Referring to FIG. 3 , MM denotes an AMF, and SM denotes an SMF.

Specifically, referring to FIG. 3 , at operation S310, the AMF canconfigure information on a data network access allowed area (DN allowedarea).

Further, at operation S320, the AMF can transmit, to the terminal,information on a PDU session usable in a list of tracking areas.

During the terminal movement, the terminal, at operation S330, mayrequest a tracking area update.

At operation S340, AMF may notify the SMF of the terminal movement inthe data network access allowed area. Accordingly, at operation S350,the SMF can transmit the data network access allowed area to theterminal during PDU session establishment.

FIG. 4 illustrates the structure of a network including a PCF.

The PCF 410 is a network function that manages the LADN policy for theterminal. The PCF can bear the responsibility for pre-installation andupdate for the LADN policy of the terminal.

Further, according to an embodiment of the present disclosure, theterminal can perform the following operations.

1) The terminal can receive usable data network information includingdata network allowed area information (it may be called serviceable areainformation).

Specifically, when the terminal performs an initial registrationprocedure or a registration update procedure, the AMF of the corenetwork may notify the terminal of data network availability andserviceable area information of the available data network.

Further, the information may include an indicator requiring immediateestablishment of the session for accessing the data network immediatelywhen the terminal enters the data network allowable area. If such anindicator does not exist, the terminal may start the sessionestablishment in need of an application program of the terminal.

2) The terminal can establish the session in the serviceable area.

If the tracking area of a base station that is currently accessed by theterminal is included in the data network allowed area (i.e., if thelocal area data network that the terminal has received is usable in thearea where the terminal is currently located), the terminal can startthe session establishment procedure. During the session establishmentprocess, the terminal can receive a total list of areas where thesession establishment is allowed. When the session is established in thedata network allowed area, the session is in an abled state.

3) The terminal can switch the session state in accordance with thelocation of the terminal.

FIG. 5 is a diagram illustrating activated and deactivated states of asession for local area data network support.

While the terminal moves in the service area after the terminal and thenetwork established the session (500), the session is maintained in anactivated state (510).

If the terminal moves to the data network allowable area (520) in astate where the session of the terminal is deactivated, the terminal canperform the registration update procedure. Specifically, the terminalrequests the registration update, the AMF notifies the SMF of locationinformation of the terminal, and the SMF changes the session state ofthe terminal from the deactivated state (530) to the activated state(510).

The SMF manages the session state, and the UPF can determine to discarduser's downlink traffic.

If the terminal gets out of the data network allowed area (540) in thesession activated state, the terminal performs the registration updateprocedure to notify the AMF of the current location of the terminal. TheAMF notifies the SMF of the current location information of theterminal, and the SMF switches the session state from the activatedstate (510) to the deactivated state (530).

If a UPF downlink packet arrives in a state where the session of theterminal is deactivated, the terminal discards the downlink packetwithout sending a data reception notification message to the SMF, thatis, without performing the paging procedure. The terminal discards anuplink packet in the session deactivated state.

Hereinafter, the above-described contents and additional contents willbe described in detail.

1. Method for Configuring a Data Network Service Area

Hereinafter, a method for configuring a data network allowed area (itmay be called a data network service area or LADN service area) will bedescribed. In the same manner as the registration area 205 of FIG. 2 ,the registration area may be configured by a set of tracking areas thatthe 5G core network allocates to the terminal. If the terminal belongsto the registration area, the registration area means an area where itis not necessary for the terminal to perform a tracking area updateprocedure for terminal mobility or a registration update procedure.

If the terminal gets out of the registration area, it should perform theregistration update procedure, and thus it is necessary to consider theregistration area when configuring a data network service area.

When configuring the data network service area, an operator should alsoconsider the registration area, and in accordance with the relationshipbetween the registration area and the data network service area, thefollowing configurations are possible as illustrated in FIG. 6 .

FIG. 6 is a diagram illustrating a data network service areaconfiguration method according to an embodiment of the presentdisclosure.

1) A case where the data network service area composed of tracking areascoincides with one registration area (610)

2) A case where the data network service area composed of tracking areasexists in one registration area (620)

3) A case where the data network service area composed of tracking areasis configured over several registration areas (630)

4) A case where the data network service area composed of a set of cellsis configured within one registration area (640)

Further, although not illustrated in FIG. 6 , the data network servicearea may be configured as follows.

5) A case where the data network service area composed of tracking areasis configured by a plurality of registration areas

6) A case where the data network service area is configured by one wholeoperator network

Separately from those as described above, if one terminal belongs to twoor more local area data networks, an intersection of two data serviceareas may not exist or may exist, as illustrated in FIGS. 7A and 7B, inaccordance with the respective service areas of the two or more localarea data networks.

FIGS. 7A and 7B are diagrams illustrating an example of a data networkservice area configuration method according to an embodiment of thepresent disclosure.

Referring to FIGS. 7A and 7B, the data network service area may beconfigured so that an overlapping area exists between areas, such as anarea allowed for data network 1 (data network service area 1, zone A)710 and an area allowed for data network 2 (data network service area 2,zone B) 720.

Further, the data network service area may be configured so that anoverlapping area exists between areas, such as an area allowed for datanetwork 2 (data network service area 2, zone B) 720 and an area allowedfor data network 3 (data network service area 3, zone C) 730.

2. Method for Receiving (or Discovering) Local Area Data NetworkInformation of a Terminal

Hereinafter, a method for receiving local area data network informationof a terminal will be described.

If the terminal initially accesses a mobile communication network orleaves from a registration area, or in order to periodically notify thenetwork that the terminal is in a call receivable state, the terminalperforms the registration procedure. If a local area data network towhich the terminal belongs is included in the registration area wherethe terminal performs the registration procedure while the networkregistration procedure is performed, the network notifies the terminalof data network information available to the terminal.

The above-described procedure may be performed as illustrated in FIGS.8A and 8B.

FIGS. 8A and 8B are diagrams illustrating a procedure in which aterminal receives local area data network information.

Referring to FIGS. 8A and 8B, the terminal may perform the registrationprocedure. The registration procedure may be performed by the terminalas illustrated in the drawings, and the detailed explanation thereofwill be omitted.

On the other hand, in the 22^(nd) procedure, the AMF in the network cantransmit local area data network (LADN) information to the terminal. Thelocal area data network information includes a data network name (DNN)for discriminating the local area data network and data network allowedarea information. The DNN information may be called data networkidentification information. As exemplarily described above, the datanetwork allowed area information may be the current registration area, aset of tracking areas, a set of cells, a plurality of registrationareas, or the whole operator area.

Further, the data network information may include an indicatorindicating that the data network corresponding to the DNN can be usedonly in a specific area.

3. Procedure for Establishing a Local Area Data Network Session of aTerminal

Hereinafter, a procedure for establishing a local area data networksession of a terminal will be described.

As described above, the terminal performs the registration procedure,and can be aware of the data network service area. The terminal can beaware of what tracking area corresponds to the currently accessiblecell. If the currently accessed cell is included in the data networkservice area received in the registration procedure, the terminal can beaware that it can be connected to the corresponding local area datanetwork.

If the terminal can be aware that it can establish a connection to thecorresponding local area data network through tracking area informationor cell information broadcasted in the current cell, and an applicationlayer program of the terminal requires data network connectionestablishment, the terminal performs a session establishment procedurefor establishing the local area data network connection. That is, if theterminal is located in the data network allowed area, and theapplication layer program requests the session establishment directly orindirectly, the terminal performs a session establishment procedure asexemplified in FIGS. 9A and 9B.

FIGS. 9A and 9B are diagrams explaining a local area data networksession establishment procedure.

Referring to FIGS. 9A and 9B, at operation 1, the terminal may includeinformation capable of indicating the local area data network (e.g., DNNinformation) in a session establishment request message to betransmitted to the network.

At operation 2, if the AMF receives the DNN corresponding to the localarea data network, the AMF identifies if the terminal can establish thesession for the local area data network connection requested by theterminal in the current location.

At operation 3, the AMF sends a local area data network (LADN) allowableindicator to the SMF. As can be identified at operation 3, the AMF mayinclude the LADN allowable indicator in an SM request message to betransmitted to the SMF.

Thereafter, at operation 4, the SMF receives local area data networksubscription information from a UDM, and identifies data networksubscription information of the terminal.

At operation 5, allowance and authentication of the PDU session may beperformed between the terminal and the network, and at operation 6, theSMF may select the PCF and establish the PDU-CAN session.

Further, at operation 7, the SMF checks whether to allow the datanetwork.

If the SMF allows the data network, the SMF may establish or correct thePDU-CAN session at operation 8, and may transmit an N4 sessionestablishment/correction request message and receive a correspondingresponse message at operation 9.

At operation 10, the SMF transmits, to the AMF, an LADN indicatorindicating that the corresponding session is the local area data networktogether with a message for allowing the session. Thereafter, if aservice request is received from the corresponding terminal outside aserviceable area, the AMF that has received the indicator rejects thecorresponding request. The subsequent process may be performed asillustrated in the drawing, and the detailed explanation thereof will beomitted.

If the SMF does not allow the data network, at operation 10, the SMFtransmits a session request rejection message to the terminal throughthe AMF. The rejection message includes an indicator indicating that thesession establishment is not allowed in the current area.

If the DNN requested by the terminal is the DNN to which the terminaldoes not belong, the SMF transfers a rejection code representing“Session establishment is not allowed due to non-subscription of therequested DNN” to the terminal. If the DNN requested by the terminal isnot allowed in the current location of the terminal, the SMF transfers arejection code representing “DNN requested in the current location isnot allowed” to the terminal.

As another method for implementing the embodiment, if the terminalrequests the session establishment in an area that is not the LADNallowed area, and if the user terminal is a non-subscriber or thecurrent location of the terminal is not the service location of the LADNto which the terminal belongs after the AMF determines whether the userterminal belongs to the LADN and the current location of the userterminal, the AMF may reject the session establishment by sending asession establishment rejection message to the terminal. Specifically,at operation 2 of FIG. 9 , the AMF immediately transmit a PDU sessionrejection message to the terminal through a RAN without transmitting asubsequent message after determining the rejection of the sessionestablishment.

4. Service Request Procedure for a Local Area Data Network Session

Hereinafter, a service request procedure for a local area data networksession of a terminal will be described.

In the 5G network, the service request procedure is performed in casewhere uplink traffic of the terminal exists in a terminal idle state(CM-IDLE state) where a radio resource control (RRC) connection does notexist and in case where the terminal is transitioned to an activatedconnected state (CM-CONNECTED state) where the RRC connection of theterminal exists.

In addition, in the 5G network, enabling of a selective user plane foreach session is supported with respect to the already connected session.For this, even if the terminal is in the activated connected state(CM-CONNECTED state) where the current RRC connection exists, thespecific session may stay in a deactivated state. In this case, aservice request procedure may be performed to change the session in thedeactivated state to the activated state.

In an embodiment of the present disclosure, it is recommended not tosend a service request message if uplink traffic occurs after theterminal that has established the session for the local area datanetwork in an idle state moves out of the data network service area.

If uplink traffic for the already established local area data networksession occurs in a state where the terminal in the idle state moves outof the date network service area, the terminal may perform a servicerequest as illustrated in FIG. 10 . In this case, the network grasps thecurrent location of the terminal, and rejects the service requestrequested by the terminal together with a rejection code representingthat the corresponding session of the terminal is not allowable in thecurrent area.

FIG. 10 is a diagram describing such a procedure in detail.

FIG. 10 is a diagram explaining a local area data network sessionservice request procedure.

Referring to FIG. 10 , at operation 1, the terminal may transmit aservice request. At operation 2, a base station that has received therequest may transmit an N2 message including the service request to theAMF.

At operation 2 a, the AMF may determine whether the local area datanetwork session is allowable in the area where the terminal has sent theservice request message.

At operation 4 a, the AMF sends a local area data network (LADN)allowable indicator to the SMF to notify of whether the local area datanetwork session is allowable.

If the AMF determines that the local area data network is not allowed inthe corresponding area, the AMF, at operation 5, rejects the servicerequest together with the rejection code notifying the terminal of “Thecorresponding session connection is not allowed in the current area”.

In contrast, if the local area network is allowed in the correspondingarea, the AMF, at operation 5, may transmit an N2 request. Asillustrated in the drawing, the subsequent process may be performed, andthe detailed explanation thereof will be omitted.

5. Terminal Operation in Case where a Destination Packet Arrives whenthe Terminal is Out of the Local Area Data Network Service Area

When the terminal in an idle state is out of the local area data networkservice area, a terminal destination packet may arrive at the UPF. Inthis case, the UPF sends a downlink packet arrival notification to theSMF, and the SMF transfers a downlink packet arrival notificationmessage again to the AMF. The AMF determines that the terminal is in anidle state, and awakes the terminal by sending a paging message to theterminal.

If the terminal receives the paging message, it sends the servicerequest to the network to attempt transition to an activated connectedstate. If the terminal sends the service request, the AMF determinesthat the session requesting the downlink packet notification requestedby the SMF is a local area data network session and the terminal islocated in the area where the corresponding session is currentlyallowable, and rejects the service request from the correspondingterminal.

6. Terminal Operation by a Local Area Data Network Policy

The 5G network manages a policy for controlling the operation of theterminal through a policy control function (PCF), and installs thepolicy in the terminal.

If the terminal initially accesses or the policy for the terminal isupdated, the 5G network may install or update the terminal relatedpolicy in the terminal. Representatively, the terminal related policy isa user traffic routing selection policy (URSP) of the terminal.

In an embodiment of the present disclosure, the terminal policy relatedto the local area data network of the terminal will be described. Inthis embodiment, explanation will be made with respect to a local areadata network (LADN) entry policy indicating the terminal operation whenthe terminal detects the entry into the data network service area and alocal area data network (LADN) exit policy indicating the terminaloperation when the terminal detects the exit from the data networkservice area.

If the terminal initial access procedure, registration update procedure,or the PCF is necessary, the PCF of the 5G network may configure theterminal LADN entry policy and LADN exit policy in the terminal.

As described above, in case of receiving the usable local area datanetwork information, the terminal receives the available data networkservice area information, and detects the entry into the configured datanetwork allowed area from the received service area information.

In case of detecting the entry into the data network allowed area, theterminal performs an operation prescribed by the LADN entry policyreceived from a policy control server. For example, if the LADN entrypolicy instructs the terminal to establish the session, the terminalperforms the session establishment procedure. Further, if the LADN entrypolicy prescribes the terminal to perform the registration updateprocedure, the terminal performs the registration update procedure.

In case of detecting leaving from the data network allowed area, theterminal performs an operation prescribed by the LADN exit policyreceived from the policy control server. For example, if the LADN exitpolicy prescribes the terminal to perform the registration updateprocedure for the network session disconnection or deactivation, theterminal performs the registration update procedure. Further, if theLADN exit policy instructs the terminal to disconnect the correspondingsession, the terminal performs the session disconnection procedure.

7. Change of the Terminal Route Selection Policy in Accordance withEntry into or Exit from the Data Network Service Area

The 5G network manages a policy for controlling the operation of theterminal through a policy control function (PCF), and installs thepolicy in the terminal.

If the terminal initially accesses or the policy for the terminal isupdated, the 5G network may install or update the terminal relatedpolicy in the terminal. Representatively, the terminal related policy isa terminal (UE) route selection policy (URSP). The UE route selectionpolicy is used by the terminal, and may be used to determine whatsession of established sessions the traffic transmitted from theterminal is routed to. The URSP may trigger a new session establishment.The UE route policy may include one or more of the following policies.

1) Service and session continuation (SSC) mode selection policy

2) Network slice selection policy

3) DNN selection policy

4) Non-seamless offloading policy

In this embodiment, a case is assumed, in which a method capable ofrouting the application program traffic of the terminal to the localarea data network is used through the DNN selection policy prescribingthe application program traffic of the terminal is routed to the localarea data network. In this case, this embodiment proposes a method foractivating or deactivating the DNN selection policy in accordance withthe terminal movement in the local area data service area.

That is, in the present disclosure, in accordance with the data networkservice area information received by the terminal through theregistration procedure, the DNN selection policy for the traffic routingof the terminal to use the local area data network is activated when theterminal enters the data network service area divided through the DNN.Further according to the present disclosure, when the terminal leavesfrom the data network service area, the corresponding DNN selectionpolicy is deactivated.

8. Method in which Available LADN Information is not Repeatedly Received

The terminal receives LADN information from the AMF of the 5G corenetwork during performing of the registration procedure. In case ofperforming a periodic registration procedure, the terminal can preventreception of the same LADN information in the registration area wherethe previous registration procedure was performed.

Specifically, the terminal stores the LADN information initiallyreceived in the same registration area. If the terminal performs theregistration procedure in the same registration area as the previousregistration area in the periodic registration procedure, the AMF canomit transmission of the LADN information.

As another method for preventing repeated reception of the same LADNinformation, the AMF may allocate an identifier indicating theconfigured LADN information, and may send the identifier to the terminalinstead of the LADN information. The identifier indicating the LADNinformation can be solely allocated in an AMF pool area. For reference,the AMF pool area is an area in which the terminal can receive a servicewithout the necessity of changing a serving AMF, and one AMF pool areameans an area in which the terminal can be serviced by one or more AMFs.The AMF pool area may be composed of collected tracking areas, and theAMF pool areas may overlap each other.

When the terminal performs the registration procedure for mobilitymanagement in case of using the above-described method, the AMF includesan identifier for discriminating the LADN information in the LADNinformation to be transmitted to the terminal. The terminal maintainsand manages the LADN information. In case where the terminal performsthe periodic registration procedure, the AMF transmits the identifier ofthe LADN information to the terminal instead of sending the LADNinformation. If the LADN information corresponding to the identifier ofthe LADN information does not exist in the terminal, the terminal mayseparately request the LADN information from the AMF by including anindicator for requesting the LADN information in the UE configurationinformation update procedure or registration update procedure.

In case where the terminal establishes the corresponding LADN session,the AMF can be aware of this in the session establishment procedure, andthe AMF can omit the transmission of the LADN information in theterminal registration update procedure while the LADN session isestablished.

9. Schemes for Providing Additional Information to Determine Whether toAccess the LADN Service

When the terminal enters the registration area including the LADN, theAMF of the 5G core network provides the LADN information to theterminal. The LADN information includes service area information (datanetwork allowed area information) in which the DNN and LADN services,which are discriminators of the data network, can be provided.

In this embodiment, a method for providing additional information fordetermining whether the terminal establishes the session in the LADNinformation will be described. The terminal determines the LADN sessionestablishment in case where an application program of the terminalrequest the corresponding DNN access through a direct API or data isgenerated from the application program of the terminal using thecorresponding DNN in accordance with the terminal route informationpolicy as described above.

The network includes the additional information for the terminal toaccess the LADN session in the LADN information to be transmitted to theterminal so that the terminal can use the information as information fordetermining whether to access the LADN session. The additionalinformation may include the following information.

1) Session supplier information: Information of an operator providingthe session. For example, a regional operator (e.g., regional operatoror public institution operator in shopping mall/airport), Internetservice provider, visited network service provider, or home networkservice provider

2) Session billing information: Non-billing, volume-rate billing,billing for use amount quota, and time-based billing

3) QoS information provided by the session: Maximum transmission ratethat can be provided, and maximum delay time

4) RAT and frequency information used by the session: 3G/4G/5Ginformation, used frequency information

5) Session authentication information: Authentication method (EAP methodinformation), and credential information required for the authentication(e.g., certificate or ID/PW type)

6) Initial accessed page information after session establishment: URLinformation to be accessed after the session access

The terminal receives the above-described information on the LADN,determines the session access/non-access, and determines anauthentication method necessary in the session access process.

7) Service information that can be provided by the session: For example,VoLTE service, IPTV service, remote file providing service, high-speedstreaming service, VR/AR service and V2X service

8) Other session information: For example, information notifying whetherthe session is a subscriber-based session or a session that can beprovided to all subscribers of an operator

FIG. 11 is a diagram illustrating the structure of a terminal accordingto an embodiment of the present disclosure.

Referring to FIG. 11 , in an embodiment of the present disclosure, aterminal may include a transceiver and a controller. Further, thecontroller may include at least one processor. The transceiver may becomposed of a transmitter and/or a receiver. The transceiver maytransmit and/or receive a signal. The controller may control the overalloperation of the terminal. The controller may control the operation ofthe terminal as described above through FIGS. 1 to 10 .

In addition to the terminal, each entity of FIG. 7 may include atransceiver and a controller. The transceiver of the entity may transmitand/or receive a signal, and the controller may control the operation ofthe entity as described above in the embodiments of the presentdisclosure.

For example, FIG. 12 illustrates the structure of an AMF, and FIG. 13illustrates the structure of an SMF.

FIG. 12 is a diagram illustrating the structure of an AMF according toan embodiment of the present disclosure.

In an embodiment of the present disclosure, an AMF may include atransceiver and a controller. Further, the controller may include atleast one processor.

The transceiver may be composed of a transmitter and/or a receiver. Thetransceiver may transmit and/or receive a signal.

The controller may control the overall operation of the AMF. Thecontroller may control the operation of the AMF as described abovethrough FIGS. 1 to 10 .

FIG. 13 is a diagram illustrating the structure of an SMF according toan embodiment of the present disclosure.

In an embodiment of the present disclosure, an SMF may include atransceiver and a controller. Further, the controller may include atleast one processor.

The transceiver may be composed of a transmitter and/or a receiver. Thetransceiver may transmit and/or receive a signal.

The controller may control the overall operation of the SMF. Thecontroller may control the operation of the SMF as described abovethrough FIGS. 1 to 10 .

Meanwhile, preferred embodiments of the present disclosure disclosed inthis specification and drawings and specific terms used therein areillustrated to present only specific examples in order to clarify thetechnical contents of the present disclosure and help understanding ofthe present disclosure, but are not intended to limit the scope of thepresent disclosure. It will be evident to those skilled in the art thatvarious implementations based on the technical spirit of the presentdisclosure are possible in addition to the disclosed embodiments.

What is claimed is:
 1. A method performed by a session managementfunction (SMF) entity in a communication system, the method comprising:receiving, from an access and mobility management function (AMF) entity,a request message for establishment of a protocol data unit (PDU)session for a local area data network (LADN) with respect to a terminal;transmitting, to the AMF entity, a response message for theestablishment of the PDU session for the LADN as a response to therequest message; and after the establishment of the PDU session for theLADN, in case that the SMF entity is notified from the AMF entity thatthe terminal moves out of an LADN service area that is a set of trackingareas (TAs) for the LADN, deactivating a user plane connection for thePDU session for the LADN while maintaining the PDU session for the LADN,wherein downlink data for the PDU session is discarded.
 2. The method ofclaim 1, wherein the response message is a reject message in case thatthe terminal is out of the LADN service area.
 3. A method performed byan access and mobility management function (AMF) entity in acommunication system, the method comprising: transmitting, to a sessionmanagement function (SMF) entity, a request message for establishment ofa protocol data unit (PDU) session for a local area data network (LADN)with respect to a terminal; and receiving, from the SMF entity, aresponse message for the establishment of the PDU session for the LADNas a response to the request message, wherein, after the establishmentof the PDU session for the LADN, in case that the AMF entity notifiesthe SMF entity that the terminal moves out of an LADN service area thatis a set of tracking areas (TAs) for the LADN, a user plane connectionfor the PDU session for the LADN is deactivated while maintaining thePDU session for the LADN and downlink data for the PDU session isdiscarded.
 4. The method of claim 3, wherein the response message is areject message in case that the terminal is out of the LADN servicearea.
 5. The method of claim 3, further comprising: receiving a requestmessage for a registration with the terminal, the request messageoriginating from the terminal; and transmitting, toward the terminal, anaccept message as a response to the request message for theregistration, the accept message including a data network name (DNN) ofthe LADN and the LADN service area.
 6. The method of claim 3, furthercomprising: receiving, from the terminal, a message for requesting theestablishment of the PDU session for the LADN in case that the terminalis in the LADN service area, the message originating from the terminal.7. A session management function (SMF) entity in a communication system,the SMF entity comprising: a transceiver; and a controller coupled withthe transceiver and configured to: receive, from an access and mobilitymanagement function (AMF) entity, a request message for establishment ofa protocol data unit (PDU) session for a local area data network (LADN)with respect to a terminal, transmit, to the AMF entity, a responsemessage for the establishment of the PDU session for the LADN as aresponse to the request message, and after the establishment of the PDUsession for the LADN, in case that the SMF entity is notified from theAMF entity that the terminal moves out of an LADN service area that is aset of tracking areas (TAs) for the LADN, deactivate a user planeconnection for the PDU session for the LADN while maintaining the PDUsession for the LADN, wherein downlink data for the PDU session isdiscarded.
 8. The SMF entity of claim 7, wherein the response message isa reject message in case that the terminal is out of the LADN servicearea.
 9. An access and mobility management function (AMF) entity in acommunication system, the AMF entity comprising: a transceiver; and acontroller coupled with the transceiver and configured to: transmit, toa session management function (SMF) entity, a request message forestablishment of a protocol data unit (PDU) session for a local areadata network (LADN) with respect to a terminal, and receive, from theSMF entity, a response message for the establishment of the PDU sessionfor the LADN as a response to the request message, wherein, after theestablishment of the PDU session for the LADN, in case that the AMFentity notifies the SMF entity that the terminal moves out of an LADNservice area that is a set of tracking areas (TAs) for the LADN, a userplane connection for the PDU session for the LADN is deactivated whilemaintaining the PDU session for the LADN and downlink data for the PDUsession is discarded.
 10. The AMF entity of claim 9, wherein theresponse message is a reject message in case that the terminal is out ofthe LADN service area.
 11. The AMF entity of claim 9, wherein thecontroller is configured to: receive a request message for aregistration with the terminal, the request message originating from theterminal, and transmit, toward the terminal, an accept message as aresponse to the request message for the registration, the accept messageincluding a data network name (DNN) of the LADN and the LADN servicearea.
 12. The AMF entity of claim 9, wherein the controller isconfigured to receive, from the terminal, a message for requesting theestablishment of the PDU session for the LADN in case that the terminalis in the LADN service area, the message originating from the terminal.